Infusion of drugs

ABSTRACT

An at least partly implantable system for injecting a substance into a patient&#39;s body, in particular a penis erection stimulation system, comprises an infusion device ( 11 ) adapted for implantation inside the patient&#39;s body and at least one reservoir (R 1 , R 2 ) adapted for implantation inside the patient&#39;s body in fluid connection with the infusion device to supply to the infusion device a substance to be injected into the patient&#39;s body. The reservoir comprises at least one first compartment accommodating or adapted to accommodate a first substance and at least one second compartment accommodating or adapted to accommodate a second substance, in particular a drug for stimulating penis erection. As a penis erection stimulation system, the infusion device preferably comprises one or more infusion needles disposed within and implanted along with one or more housings adjacent the patient&#39;s left and right corpora cavernosa. A pump may be implanted inside the patient&#39;s body to supply the infusion needle with infusion liquid. A drive unit also adapted for implantation inside the patient&#39;s body may be arranged for advancing and retracting the tip end of the infusion needle such that it penetrates the housing at least in two different penetration areas either simultaneously or in immediate time succession, thereby injecting drugs along with the infusion liquid into the patient&#39;s body for stimulating penis erection.

This application is the U.S. national phase of International ApplicationNo. PCT/EP2009/007295, filed 9 Oct. 2009, which designated the U.S. andclaims the benefit of U.S. Provisional No. 61/136,880 filed 10 Oct.2008, the entire contents of each of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention relates generally to the infusion of a substance,in particular drugs, into a patient's body and, more specifically, tothe stimulation of penis erection.

When a male is stimulated erotically, connections between arteries andveins are closed (arteriovenous anastomoses) so that blood which isnormally able to bypass the empty spaces or sinuses of the corporacavernosa is retained in the penis.

The main vessels supplying the blood to the cavernous spaces in theerectile tissue of the corpora cavernosa are the deep arteries of thepenis. They are therefore heavily involved in the erection of the penis.They give off numerous branches—the helicine arteries—that open directlyinto the cavernous spaces. When the penis is flaccid, these arteries arecoiled, restricting blood flow. However, the smooth muscle in the coiledhelicine arteries relaxes as a result of parasympathetic stimulation. Intheir relaxed state, the helicine arteries straighten, enlarging theirlumina and allowing blood to flow into and dilate the cavernous spacesin the corpora of the penis at arterial pressure. In combination withthe bulbospongiosus and ischiocavernosus muscles compressing the veinsegressing from the corpora cavernosa, the erectile bodies of the penisbecome enlarged and rigid, and an erection occurs.

Patients suffering from erectile dysfunction can cause the penis tobecome turgid by injecting into the corpora cavernosa a medicament, suchas papaverine or prostaglandin E1, causing the smooth muscles to relax.The patients have to learn a certain technique under doctor'ssupervision in order to be able to properly inject the medicament ineach of the corpora cavernosa. Only after about 15 minutes afteradministration of the medicament will the medicament become effective.Furthermore, the available medicaments are only stable as a drysubstance (and typically cooled). Consequently, since long term storageof drugs stimulating penis erection is not possible with many currentlyavailable drugs, the drug to be injected would typically be provided asa first substance, such as a saline solution, to be mixed with a second,dry substance for injection shortly before the injection is performed.Thus, the entire procedure is inconvenient for the patient, the more soas proper administration and dosing is critical since the medicament maybe transported with the blood into other regions of the patient's bodyif the injection is not done properly.

Recently, a different method has become known under the brand Muse®. Inthis method, a plastic rod comprising the medicament alprostadil isinserted into the urethra. Upon pressing a button, the alprostadil isreleased from the rod into the urethra. After removal of the plasticrod, the penis is rolled between the palms of the hands so that themedicament dissolves, distributes and is absorbed through the urethrawall. However, proper dosage and administration is also critical in thismethod.

The afore-mentioned problems are not limited to the administration ofdrugs stimulating penis erection. Similar problems can also occur inother applications where long term storage of a drug to be injected isdifficult and, therefore, the drug must be kept cool and mixed togetherwith other substances shortly before administering it to the patient.

It is therefore the object of the present invention to improve theadministration of a drug into a patient's body, and more specifically toimprove the stimulation of penis erection, so that the entire process ismore reliable and more convenient for the patient.

SUMMARY OF THE INVENTION

The essence of the invention lies in injecting a substance into thepatient's body using an implantable infusion device. This will greatlyimprove the patient's comfort as he no longer needs to pierce himselfwith an infusion needle, which for many people is not an easy task.Furthermore, due to the permanent implantation of the infusion device,the injection will always occur at the proper location, said locationbeing selected such that the drug is most effective. While there aremany conceivable technical variations for injecting the drug through theinfusion device into the patient's body, such injections are definitelymore convenient for the patient once the infusion device has beenimplanted as compared to the alternative of injecting the drug fromoutside the patient's body.

According to the present invention, in addition to the implantableinfusion device at least one implantable reservoir is provided in fluidconnection with the infusion device to supply to the infusion device asubstance to be injected into the patient's body. More specifically, thereservoir has at least one first compartment, e.g. for accommodating aninfusion liquid such as a saline solution, and at least one secondcompartment, e.g. containing a drug, in particular a drug in dry form,for mixing with the infusion liquid of the first compartment. The drugmay be in powder form and, more specifically, may be a freeze-drieddrug. In particular, the drug contained in the second compartment wouldbe a drug for stimulating penis erection. A mixing chamber may beprovided for mixing the substance from the first compartment with thesubstance from one or more of the at least one second compartment.

The number of the second compartments may be huge, such as 50 or more,in particular 100 or more. This would not constitute a particularproblem in terms of space constraints since the amount of drugs requiredfor each stimulation of penis erection is extremely little and wouldamount to a few micrograms. Furthermore, the reservoir may be adaptedfor implantation within the patient's body remote from the housingcontaining the needle, such as close to the symphyseal bone. There is alot of space available above the patient's symphyseal bone, and thedrugs could be delivered to the infusion device through an appropriateconduit. If desired, one can inject pure saline solution after the druginjection has been completed so as to clean the conduit and infusiondevice from any drug residue.

Preferably, the second compartments containing the drug areliquid-tightly sealed against the first compartment, with a mechanismbeing provided for individually opening a connection between the secondcompartments and the first compartment.

According to a preferred embodiment, the second compartments are mountedin a plate so as to open towards a first side of the plate and theopening mechanism is adapted to act on the second compartments from asecond side of the plate opposite the first side of the plate so thatthe compartments open to the first side of the plate. Thus, the secondcompartments may be pushed from their rear side (second side of theplate) so as to open frontward into e.g. a mixing chamber in which thecontent of the opened second compartments mixes with the content of thefirst compartment of the reservoir, such as with saline solution. Morespecifically, the second compartments may be mounted in the plate asdisplaceable drug containers and the opening mechanism may be adapted todisplace the drug containers such that they deliver their drug contentsin the manner described.

Alternatively, the plate may be rotatable so as to allow the drugcontainers to be brought into alignment with a conduit upon rotation ofthe plate. Thus, when the drug is brought into alignment with suchconduit, it may be mixed with e.g. saline solution pumped through theconduit towards the infusion needle.

According to another preferred embodiment, the second compartments aremounted on a tape wound up on a reel. A plurality of rows of the secondcompartments may be arranged on the tape in side-by-side relationship ina direction different to the winding direction of the tape. This way,the length of the tape can be reduced. It is particularly preferable ifthe tape is contained in a replaceable cassette. Thus, when all of thesecond compartments of the tape are emptied, the tape can be easilyreplaced by replacing the cassette.

As mentioned above, while the reservoir may generally be part of thehousing accommodating the at least one infusion needle, it is preferredto arrange the reservoir separate from the housing for remoteimplantation within the patient's body.

At least a section of a periphery of the first compartment of thereservoir may be made from a flexible material permitting volume changesof the first compartment by deformation of the flexible material asinfusion liquid is filled into or drawn out of the reservoir. Thus, thereservoir may be of balloon type. The flexible material may comprise apolymer membrane. A bellows construction is preferable having pre-bentcreases to reduce long term degradation.

According to a particular embodiment, drawing liquid from the reservoirmay cause a pressure decrease in at least part of the reservoir so thata negative pressure is attained as compared to the pressure in front ofthe infusion needle. For instance, the first compartment of thereservoir may comprise a gas chamber and a liquid chamber, said chambersbeing separated by a membrane, e.g. the polymer membrane. When liquid isdrawn from the liquid chamber, the pressure in the gas chamber willdecrease accordingly.

The reservoir may have an injection port for injecting liquid fromoutside the human body into the implanted reservoir. That way, thereservoir implanted in the patient's body along with the infusion devicemay be kept relatively small since the reservoir can be refilled easilyat appropriate time intervals, possibly with a doctor's aid.

Preferably, the injection port comprises a self-sealing material inrespect of penetrations caused by a replenishing syringe that would betypically used to refill the reservoir through the patient's skin. It ispreferable to implant the self-sealing injection port of the reservoirsubcutaneously in the patient's body so that it is easily accessible forrefill by means of the syringe.

The conduit or conduits for connecting the remotely implanted reservoirwith the infusion device should have a length sufficient to bridge thedistance between the patient's symphyseal bone and the inferior fasciaof the patient's urogenital diaphragm, where the housing is preferablyto be placed. Accordingly, the conduit should have a length of 10 cm ormore.

While it has already been pointed out that drugs, in particular thedrugs for stimulating penis erection, may degrade upon long termstorage, another important influence on drug degradation is the storagetemperature. Some drugs have to be stored in a refrigerator at low or atleast moderate temperature. A preferred embodiment of the inventiontherefore provides for a cooling device for keeping the content withinat least one compartment of the reservoir at a temperature below 37° C.This can be achieved with relatively little energy supply if the amountof drugs to be cooled is extremely little, as explained above, and iffurthermore the drug compartment within the reservoir is thermallyinsulated. For instance, the reservoir may be comprised in an insulationchamber.

It is preferred to provide the cooling device with a heat exchanger forexchanging with the patient's body heat generated by the cooling device.Such heat exchanger may be implanted within the patient's body remotefrom the cooling device to safely dissipate the heat energy in an areawhere it cannot adversely affect the content of the reservoir.

The cooling device can be of a variety of different types. According toa first embodiment, the cooling device may contain at least twodifferent chemicals reacting with each other, thereby consuming thermalenergy which energy is drawn from the contents within the reservoir sothat a cooling effect on the contents is achieved. The two chemicals maybe provided in separate chambers and a flow control device may beprovided to bring together certain amounts of the two differentchemicals so as to control the amount of thermal energy drawn from thecontents within the reservoir.

According to a second embodiment, the cooling device may comprise atleast one Peltier element. A Peltier element is an electrothermalconverter causing a temperature difference to occur when an electriccurrent is flowing through the element, based on the Peltier effect.While one part of the Peltier element cools down, a different partthereof heats up. Such heat may again be removed by means of a heatexchanger or simply by providing the particular part generating the heatwith an enlarged surface so that the heat is directly dissipated intothe adjacent body part of the patient.

According to a third embodiment, the cooling device may be of arefrigerator-type construction. That is, heat exchanging pipes within achamber to be cooled and heat exchanging pipes outside the chamber fordissipating the heat energy absorbed in the cooling chamber are providedalong with a compressor for compressing the refrigerant gas when itexits the cooling chamber and an expansion valve for expanding therefrigerant gas before it re-enters the cooling chamber.

The implantable infusion device of the system preferably comprises oneor more infusion needles designed to permanently reside within thepatient's body. Such a system with only one infusion needle is generallyknown from WO 2007/051563. At least one drive unit is coupled to theinfusion needle or needles and arranged for advancing the tip endthereof to penetrate any fibrosis when the system is implanted in thepatient's body. At least the infusion needle or needles and the at leastone drive unit are designed for implantation in the patient's body alongwith the reservoir. Preferably, at least one pump, which is preferablyalso adapted for implantation inside the patient's body, is provided toadvance the substance to be injected from the reservoir to the infusiondevice. Other components such as an energy source, a control unit and/ora data processing device may be extracorporal to complete the system.However, it is preferred that the aforementioned components be implantedas well, suitably forming an integral part with the remaining componentsof the system so as to be implantable as a unitary piece.

The infusion needle or needles may rest at the implantation site over along time either for single use or for multiple use. For instance, whereit is likely that a patient will suffer an allergic attack, such assevere allergic reactions affecting e.g. the respiratory tract, in thenear future or possibly only within a year or two, the infusion needleand possibly the entire system may be implanted in the patient's bodyfor single use at the appropriate time. Over time, fibrosis will grow onthe system. However, at the time of use, the infusion needle may beadvanced by the drive unit so as to penetrate any fibrosis, therebyallowing immediate drug delivery from the reservoir through the tip endof the infusion needle into the patient's body. Where the infusionneedle is implanted adjacent a blood vessel, the tip end of the infusionneedle may be advanced into the blood vessel without any risk offormation of thrombosis (nicht fibrosis?) prior to use.

Where the system is implanted for multiple use, the drive unit ispreferably configured for advancing and retracting the tip end of theinfusion needle. Thus, each time when the drug is delivered to thepatient, the infusion needle will be advanced, the drug injected and theinfusion needle retracted again.

Preferably, the infusion needle is disposed within a housing of theinfusion device with the tip end of the infusion needle being arrangedfor passing through an outer wall of the housing. This prevents anyfibrosis from growing into the infusion needle, in which case theinfusion needle would still be blocked even after penetrating anyfibrosis that has built up in front of the needle. In the case ofmultiple use, it is preferred when the at least one drive unit iscoupled to the at least one infusion needle so as to advance and retractthe tip end of the at least one infusion needle in such a way that itpenetrates at least two different penetration areas within the housing'souter wall, so as to allow for injecting the substance through said atleast two different penetration areas via the at least one infusionneedle. For instance, the at least one needle may be arranged forpenetrating the at least two different penetration areas eithersimultaneously (e.g. where a plurality of needles, i.e. at least twoneedles, are provided) or in immediate time succession (e.g. where asingle needle is provided). Also, where more than one needle isprovided, they may be arranged in separate housings.

More specifically, in order to stimulate penis erection, the substancemay be injected into both the right and left corpus cavernosum and/orinto the two deep arteries thereof and/or possibly into muscle tissueregulating blood flow through the right and left corpus cavernosumand/or into tissue in close proximity to the left and right corpuscavernosum, by means of an infusion device permanently implanted at anappropriate location inside the patient's body. Accordingly, the housingor housings accommodating the at least one infusion needle arepreferably adapted for implantation inside the patient's body adjacentthe two corpora cavernosa and/or the two deep arteries thereof and/oradjacent muscle tissue regulating blood flow through the patient's leftand right corpus cavernosum and/or adjacent tissue in close proximity tothe two corpora cavernosa. The distance between the two differentpenetration areas to be penetrated by the at least one infusion needleis selected such that the respective parts of the patient's body arepierced whenever the drug is to be injected. As will be described below,two or more infusion needles may be provided in order to inject the drugin the two or more different penetration areas, or a single infusionneedle may be provided along with an appropriate drive unit fordisplacing the tip end of the infusion needle so as to penetrate thehousing's outer wall in the respective different penetration areas.

Preferably, a single command or single action from the patient issufficient for injecting the substance through the at least twopenetration areas, either due to a corresponding mechanical structure ofthe drive unit or due to a suitably configured control unit controllingthe drive unit. This will make the handling of the system easy for thepatient.

Where two different penetration areas are pierced in immediate timesuccession, the time delay between the penetration of the first and thesecond of the penetration areas is preferably as short as possible, morepreferably less than 120 seconds, and most preferably less than 60seconds. This can be achieved by means of a properly controlled driveunit. A longer time delay would be inconvenient for the patient.Therefore, it is preferred that, once the infusion needle has beenretracted from a first of the two penetration areas, it is immediatelyadvanced to the second of the penetration areas.

While it is possible according to one aspect of the invention toactively open the outer wall for allowing the infusion device topenetrate the wall, it is preferred according to another aspect of theinvention to arrange an infusion needle so as to penetrate the outerwall by piercing through the outer wall. For that purpose, the outerwall may either comprise flaps to be pushed aside by the infusion needleas the infusion needle is advanced, or the outer wall may be made atleast in the penetration areas from a material which is self-sealing inrespect of penetrations resulting from the at least one infusion needle.While the entire housing may be made from the self-sealing material, itis advantageous for stability reasons if the self-sealing material formsat least one window area in the outer wall, the window area beingpositioned for penetration by the tip end of the at least one infusionneedle. The window area may be formed by a self-sealing penetrationmembrane which is preferably integrated in the outer wall by pressfitting it into the outer wall.

Typically, the self-sealing material would be made from a polymermaterial which preferably comprises silicone. Other biocompatiblepolymer materials, such as polyurethane and the like, may be employed aswell.

The self-sealing material may also be a composite material. Aparticularly preferred embodiment of such composite material comprisesat least one outer shape-giving layer and a self-sealing soft materialcontained within the outer layer. Thus, the outer layer forms a shellfor the soft material. The outer layer may be made from a biocompatiblepolymer, such as one of those polymers mentioned above, and preferablythe self-sealing soft material may be a gel.

Instead of a self-sealing material, the part of the outer wall to bepenetrated by the infusion needle may comprise one or more flaps in thepenetration areas through which the infusion needle or needles can pass.This can reduce the force needed for the infusion needle to penetratethe outer wall, as compared to the penetration of a self-sealingmembrane. The flap is preferably arranged to be pushed aside by theinfusion needle upon advancement of the infusion needle.

Alternatively, the outer wall may comprise at least one door in thepenetration areas. A drive is connected to the door for actively openingthe door so as to allow for the infusion device to be advanced throughthe opened door. Again, the door may comprise a flap, such as aresilient, normally closed flap. It is particularly preferred if thedrive connected to the door forms part of the drive unit coupled to theinfusion needle. More specifically, the arrangement may be such thatadvancement of the infusion device by means of the drive unitsimultaneously causes the drive to open the door.

Where a single housing is provided for the at least one infusion needleor where two or more penetration areas are arranged in a single housing,the penetration areas may be arranged in the housing so that they can beplaced either adjacent to both the right and left corpus cavernosum ofthe patient's penis and/or the two deep arteries of the right and leftcorpus cavernosum and/or adjacent to muscle tissue regulating blood flowthrough the right and left corpus cavernosum and/or in sufficientlyclose proximity to another type of tissue allowing both the first andsecond corpus cavernosum to become turgid when the particular drug isinjected thereinto.

The at least one infusion needle preferably has a tube-like body closedat the tip end and provided with a laterally arranged delivery exit portfor delivery of the drug into the particular body part. Therefore, theneedle will not cut out any material but will simply divide it duringpenetration. Thus, when the needle penetrates any material, such asfibrosis and/or the self-sealing penetration membrane, there will be nomaterial entering and blocking the drug delivery passageway.

As mentioned above, a separate infusion needle may be provided for eachof the two or more penetration areas. Thus, where injection is desiredto occur in only two different areas to provoke penis erection, twoseparate infusion needles may be advanced through the correspondingpenetration area of the respective housing—preferably simultaneously—andretracted again after injection.

According to a preferred embodiment, two or more infusion needles areprovided for each of the different penetration areas and arranged forpenetrating different penetration sites within each of said differentpenetration areas. This allows for penetrating different sites withineach penetration area at different times, thereby giving the humantissue time to recover from the piercing by the infusion needle. Thiscan be achieved with a drive unit suitably configured to advance andretract one infusion needle in each of said different penetration areasat one time, and to advance and retract a different infusion needle ineach of said different penetration areas at a different time.

Since it is preferred for reasons of space constraints to implant thereservoir remote from the injection area or areas, it can beadvantageous to employ long infusion needles that are flexibly bendable.The tip end of such infusion needles would then be arranged within afirst housing so as to penetrate the outer wall thereof upon advancementof the long infusion needle, whereas the other end of the infusionneedle would be arranged in a second housing remotely implanted insidethe patient's body. The injection needle would be sufficiently long tobridge the distance from the second housing for remote implantation tothe first housing and further through the first housing up to the outerwall of the first housing to be penetrated by the needle. The long andflexibly bendable infusion needle may be guided within a suitablesheath. Furthermore, for reasons of space constraints, it isadvantageous to also arrange at least a part of the drive unit foradvancing and retracting the tip end of the infusion needle remote fromthe injection area, preferably within the second housing and even morepreferably in a common housing with the remotely implanted reservoir.More preferably, most or all of the active parts, such as a motor, pumpand the like, may be accommodated in the remotely implanted secondhousing, whereas the first housing only includes passive elements.

A drive unit according to the present invention includes not only thedrive itself, such as an electric motor, but also those components whichare involved in transforming the driving energy provided by the driveinto movement of the at least one needle, such as transmission gears andthe like.

For instance, in the case of the long flexibly bendable infusion needle,the drive unit may be such that the infusion needle is advanced and/orretracted by turning the infusion needle or by turning an elementcooperating with the infusion needle. More specifically, the drive unitfor advancing and retracting the infusion needle may comprise a screwdrive connection. For instance, the drive of the drive unit may turn ascrew threadingly engaged with a rack coupled to the infusion needle sothat rotation of the screw will cause the infusion needle to be advancedor retracted. The screw and rack of the screw drive connection arepreferably accommodated in the remotely implanted second housing but mayalso be arranged in the housing accommodating the tip end of the needle.Instead of the screw, the infusion needle itself may be rotated by meansof a suitable drive so that threading on the needle engaging a fixedlymounted rack causes the infusion needle to advance or retract uponrotation of the infusion needle. Between the first and second housings,the infusion needle is preferably guided in a sheath, so as to reducefriction and prevent growth of fibrosis that might hinder movement ofthe needle.

Alternatively, instead of using long and flexibly bendable infusionneedles, the infusion needles may be contained in a common housing inspaced apart relationship, with the drive unit being configured toadvance and retract the tip ends of the infusion needles so as topenetrate the outer wall of the common housing in said at least twodifferent penetration areas, again preferably simultaneously. Placingthe needles in a common housing simplifies the procedure for fixing theneedles in place close to the injection areas. Furthermore, a singledrive unit may be used for advancing and retracting the tip ends of theplurality of infusion needles, this making the entire system lessvoluminous. The use of a single drive unit is particularly advantageouswhere the drive unit is also contained in the common housing, i.e. wherethe drive unit is also to be implanted close to the very constrainedinjection area.

Again, according to a particularly preferred aspect of the invention,the tip ends of the infusion needles are laterally movable, so as tovary the penetration sites within the particular penetration areas ofthe housing's outer wall, thereby varying the injection site within theparticular injection area in the patient's body. As set out above,frequent piercing of the same body part may cause irritation, eventuallymaking further piercing difficult or even impossible. Variation of theinjection site by laterally displacing the needle upon each injectioncycle may overcome such problems. Accordingly, the drive unit in thecommon housing is preferably configured to laterally displace the tipends of the infusion needles to different penetration sites within eachof said different penetration areas. More specifically, the drive unitis preferably configured to laterally displace the tip ends of theinfusion needles simultaneously. This can be achieved e.g. by jointlymounting the infusion needles on a movable carriage of the drive unit,such as a turntable and/or a shuttle, possibly in the form of a slide.Thus, the drive unit for advancing and retracting the tip ends of theinfusion needles is preferably configured so as to also laterallydisplace the tip ends of the infusion needles each time the tip ends areadvanced or retracted.

Thus, the lateral displacement and the advancement/retraction of the tipends of the infusion needles are coordinated. The lateral displacementof the tip ends of the infusion needles may take place before and/orafter an injection. The mechanism may be such that after a certainnumber of lateral displacements or after lateral displacement over apredefined distance, the tip end of the infusion needle is laterallyreturned to its initial position so that the next number of infusionswill take place again at locations that have previously been penetratedby the needle. It is even preferred to configure the drive unit suchthat the tip ends of the infusion needle are displaced in at least twodifferent lateral directions. For instance, when the infusion needle haslaterally returned to its initial position, the next number of infusionsmay take place somewhat laterally offset above or below the first numberof penetration sites. This permits a two-dimensional array ofpenetration sites to be obtained.

The infusion needles may be arranged one above the other within thecommon housing. Generally speaking, it is preferable in such a situationthat the direction of lateral displacement of the tip ends of theinfusion needle within the different penetration areas is differentfrom, in particular perpendicular to, the direction of distance betweenthe different penetration areas. Alternatively, where the infusionneedles are arranged with great lateral distance between each other, thedirection of lateral displacement of the tip ends of the infusionneedles within each of the two different penetration areas may generallybe the same as the direction of distance between the differentpenetration areas.

It is likewise possible to provide a single infusion needle within thehousing and to implant the housing within the patient's body adjacentthe two or more injection areas. In this case, the drive unit may beconfigured so as to laterally displace the tip end of the one infusionneedle between various lateral positions such that the infusion needlecan penetrate the housing's outer wall in the different penetrationareas. The distance of lateral displacement of the single infusionneedle between the different penetration areas would amount to 3 mm, 4mm, 5 mm or even more upon each successive injection. Such successiveinjections are preferably in immediate time succession, preferably notexceeding 120 seconds between two injections, more preferably notexceeding 60 seconds. Most preferably, the drive unit will be adapted toinitiate advancement of the one infusion needle to a second one of theplurality of penetration areas once it has been retracted from a firstone of the penetration areas.

An implantable infusion device comprising a single, laterallydisplaceable infusion needle contained within a housing so as topenetrate the housing's outer wall at different penetration sites isgenerally known from WO 2007/051563. However, this prior art device isneither intended nor configured for injecting drugs simultaneously orquasi-simultaneously in immediate time succession in two or moredifferent injection areas. The drive unit of the prior art device isinstead configured to administer the drug at a different penetrationsite of a single injection area at each time of operation. For instance,the prior art device may be placed along a blood vessel so as to injectdrugs at different injection sites within a single injection area of theblood vessel. Thus, the distance of lateral displacement of the tip endof the infusion needle between one injection and a next followinginjection is not configured in the prior art device such that differentinjection areas within the patient's body could be reached. Also, theprior art infusion device is not aimed at being used for the stimulationof penis erection.

Turning back to the present invention, it is again preferable, when thepatient desires to achieve another penis erection at a later point oftime, that the single infusion needle does not penetrate the samepenetration site within the particular penetration area of the housing'souter wall, but that the drive unit is configured to laterally displacethe tip end of the one infusion needle to different penetration siteswithin each of the different penetration areas. Again, the direction oflateral displacement of the tip end of the one infusion needle withineach of the different penetration areas may either be the same as thedirection of lateral displacement of the tip end of the infusion needlebetween the different penetration areas, or may be different from, inparticular perpendicular to, the direction of lateral displacement ofthe tip end of the infusion needle between the different penetrationareas. Depending upon the particular configuration of the system, thismay be achieved with a single, multifunctional drive unit or with aplurality of different drive units suitably arranged to work incoordinated fashion. Even a combination of these alternatives ispossible, leading again to a two-dimensional array of penetration siteswithin each penetration area.

Where the housing or at least the window area thereof is formedspherically, even a three-dimensional array of penetration sites throughthe housing's outer wall can be obtained by means of a suitably adapteddrive unit for the needle displacement. This greatly increases thesystem's flexibility of use.

Regardless of the number of needles involved and regardless of theparticular penetration site array to be achieved, it is preferable toconfigure the drive unit such that the lateral displacement of the tipend of the infusion needle or needles is achieved automatically duringadvancement and/or retraction of the tip end of the needle or needles.For instance, where the infusion needle is mounted on a movable carriagefor the lateral displacement of the tip end of the needle, such as on aturntable or a shuttle, e.g. in the form of a slide, the drive unit maycomprise a stepper which is adapted to automatically advance the movablecarriage a predefined distance upon each advancement and/or retractionof the infusion needle.

Turning now to the pump for advancing the infusion liquid from thereservoir to the infusion needle or needles, such pump may be a manuallydriven pump or an automatically driven pump. The manually driven pumpmay be formed from a balloon which may be manually compressed ifsuitably arranged under the patient's skin. The balloon type pump may atthe same time serve as a reservoir for the infusion liquid, inparticular for the saline solution. Preferably, however, anautomatically driven pump is used. While the type of pump is notcritical, one specific type of pump is particularly preferred. Moreparticularly, an implantable pump preferably comprises a valve devicehaving a first and a second valve member, each having a smooth surfacefacing each other so as to form a sealing contact between the first andsecond valve members and further having different liquid channels thatcan be brought into alignment by displacement of the two smooth surfacesrelative to one another while maintaining the sealing contact. This typeof pump is described in great detail in WO 2004/012806 A1. The first andsecond valve members are preferably made from a ceramic material for itsexcellent sealing capabilities over a long period of time and itsinertness to many substances.

The pump may be a membrane type pump, as also described in WO2004/012806 A1, but is not restricted to this type of pump. The membranetype pump may comprise a membrane displaceable by a piston as the pistonmoves, the piston being coupled to the valve device so as to slidablydisplace the first and second valve members relative to one another asthe piston moves. Preferably, the pump will be implanted separate fromthe housing accommodating the needle or needles for remote implantationwithin the patient's body.

Due to the space constraints within the patient's body in the area whereinjection is to take place, it is advantageous to implant as manycomponents of the system as possible remote from the housingaccommodating the infusion needle or needles. In this context, the driveunit may comprise a mechanical drive element for transmitting kineticenergy from a remote location within the patient's body to the at leastone infusion needle. The mechanical drive element may comprise arotating shaft by which a considerable distance can be bridged withinthe patient's body. The rotating shaft may, upon rotation about its axisof rotation, cause movement of the infusion needle either directly orindirectly. More specifically, the rotating shaft may be in the form ofa worm screw which, when turned, causes the infusion needle or needlesto advance and retract and/or causes the infusion needle or needles tomove laterally upon each advancement/retraction. Individual rotatingshafts or worm screws may be provided for each individual infusionneedle and/or for advancing and retracting the tip end of the infusionneedle or needles on the one hand and laterally displacing the tip endof the infusion needle or needles on the other hand. Most preferably,the rotating shaft or worm screw is flexibly bendable, so that it can befreely arranged within the patient's body. Alternatively or in addition,the drive unit may comprise at least one wire directly or indirectlycooperating with the infusion needle so as to cause movement of theinfusion needle upon actuation of the wire. Thus, the wire may be pulledat one end thereof which is located within the patient's body remotefrom the injection sites. Preferably, the wire extends through the sameconduit which connects the infusion needle or needles with thereservoir. More specifically, pulling the wire may cause the tip end ofthe infusion needle or needles to displace laterally from a first to asecond of the different penetration areas or from a first penetrationsite to a second penetration site within a single one of the differentpenetration areas. A single pulling wire may be sufficient to causemovement of the infusion needle in one direction, whereas a springelement or any other pretensioning means may be provided to urge theinfusion needle back to the initial starting position or to a differentstarting position. Alternatively, two pulling wires may be provided tomove the infusion needle back and forth in a single dimension.

According to a preferred embodiment, the infusion needle is arranged fortwo-dimensional lateral displacement. This can be achieved by means oftwo pulling wires, preferably cooperating again with spring elements orother pretensioning means to provide a counterforce to be overcome bypulling the wires. Alternatively, three pulling wires may be provided tolaterally displace the tip end of the infusion needle back and forthalong at least two directions within a two-dimensional plane.

A pulling wire may also be arranged to advance or retract the infusionneedle by pulling the wire. Again, a spring element or otherpretensioning means may be provided to urge the infusion needle back toits initial starting position or to a different starting position.

Alternatively, the drive unit may comprise a hydraulic drive fortransmitting hydraulic energy from a remote location within thepatient's body to the at least one infusion needle for advancing the tipend thereof and/or for laterally displacing the tip end thereof. Theinfusion liquid itself may be used as the hydraulic medium providing thehydraulic energy, or a secondary liquid different from the infusionliquid may be used.

Further alternatively, the drive unit may comprise one or more electricmotors inside the housing accommodating the at least one infusionneedle. In this case, energy may be transmitted from a remote locationwithin the patient's body to the at least one motor by means ofappropriate wiring. Again, as in the two afore-described alternatives, asingle motor may be provided for advancing and retracting the tip end ofthe infusion needle or needles and for laterally displacing the tip endof the infusion needle or needles, or individual motors may be providedfor each individual infusion needle and/or for advancing the tip ends ofthe infusion needle or needles on the one hand and laterally displacingthe infusion needle or needles on the other hand.

Even further alternatively, the drive unit may comprise anelectromagnetic drive for laterally displacing and/or for advancing andretracting the tip end of the infusion needle or needles. For instance,the electromagnetic drive may comprise a group of electromagnetscomposed of a plurality of laterally spaced apart electromagnet firstparts and at least one electromagnet second part, the electromagnetsecond part cooperating with an energized one of the electromagnet firstparts. The electromagnet second part is fixedly connected to theinfusion needle or needles either directly or indirectly so that uponenergization of one or more of the electromagnet first parts theelectromagnet second part and, thus, the infusion needle or needles willbe caused to move. The arrangement of the electromagnet first parts andsecond part may be such that the electromagnet first parts are arrangedin a first plane and the electromagnet second part is movable in frontof or behind the first plane. Alternatively, the electromagnet firstparts may face each other, thereby defining a first plane between them,and the electromagnet second part may be movable within the first plane.Depending on which one or ones of the electromagnet first parts areenergized, the electromagnet second part with the infusion needle orneedles fixed thereto will move accordingly. The electromagnet firstparts preferably each include a magnetic coil.

In either one of the aforementioned alternatives, it is advantageous totransmit the driving energy through the conduit that connects the atleast one infusion needle with the remotely implanted reservoir. Thatis, in the case of a mechanical drive element in the form of a wire orrotating shaft, the wire/shaft and the infusion liquid may be guidedthrough a common conduit. The common conduit may comprise two separatepaths, one for the shaft or wire and one for the infusion liquid. Such acommon conduit facilitates the handling and arrangement of the systemduring implantation. Similarly, the wiring for transmitting electricenergy to the motor or to the electromagnetic drive may be guidedthrough a conduit connecting the infusion needle or needles with thereservoir.

Where the pump and/or drive unit is not actuated manually, a drive inthe form of a motor may be arranged e.g. for electrically, magneticallyor electromagnetically actuating the pump and/or drive unit or forhydraulically actuating the pump and/or drive unit. The motor ispreferably arranged for actuating either the pump or the drive unit,thereby causing simultaneous actuation of the other, e.g. the drive unitor the pump. A motor may also be provided for actuation of any otherenergy consuming part of the infusion device. More specifically, aplurality of motors may be provided, e.g. an individual motor for eachinfusion needle and/or an individual motor for displacing the tip end ofthe infusion needle in a lateral direction on the one hand and foradvancing the tip end of the infusion needle through the housing's outerwall on the other hand.

Again, for reasons of space constraints in the area of implantation ofthe housing accommodating the infusion needle or needles, it isadvantageous to remotely implant the motor within the patient's bodyseparate from the housing. Again, actuating means may be provided formanual activation of the motor or motors, such actuating meanspreferably being adapted for subcutaneous implantation.

The term “motor” according to the present invention includes anythingthat employs energy other than manual power and either automaticallytransforms such energy into kinetic or hydraulic or another type ofenergy or directly uses such energy to activate the pump, drive unitand/or other part of the overall system. As such, it is possible thatpart of the drive unit also forms part of the motor, e.g. in the case ofan electromagnetically actuated drive unit.

Coupling elements may be provided either for conductive or for wirelessenergy transfer from outside the patient's body to the motor. Forinstance, the motor may be arranged for being wirelessly driven by anexternal electromagnetic field.

An energy source for providing energy to at least one of the pump, thedrive unit and the drive (motor) for driving the drive unit, and anyother energy consuming part of the system may be provided. For instance,an external energy source for use outside the patient's body, such as aprimary energy source or a battery, in particular a rechargeablebattery, that may be mounted on the patient's skin, may be used toprovide energy to the pump and/or drive unit and/or any other energyconsuming part of the system. The energy source may in particular beconnected to the at least one motor for actuating these components. Anexternal energy source for wireless energy transfer may be adapted tocreate an external field, such as an electromagnetic field, magneticfield or electrical field, or create a wave signal, such as anelectromagnetic wave or sound wave signal.

Where the energy is wirelessly transferred to the implanted components,a transforming device for transforming the wirelessly transferred energyinto electric energy may be provided. Such transforming device ispreferably adapted to be placed directly under the patient's skin so asto minimize the distance and the amount of tissue between thetransforming device and the energy supply means outside the patient'sbody.

Instead of or in addition to an external energy source, the system maycomprise an implantable energy source. While such implantable energysource may be part of or may be contained within the housingaccommodating the infusion needle or needles, it is preferred to providethe implantable energy source separate from the housing for remoteimplantation within the patient's body. Such implantable energy sourcepreferably comprises energy storage means, such as a long-life batteryor, more preferably, an accumulator. The accumulator has the advantageof being rechargeable. Preferably, the accumulator comprises arechargeable battery and/or a capacitor.

Again, coupling elements for conductive or wireless energy transfer froma primary energy source outside the patient's body to the accumulatormay be provided for charging the accumulator from outside the patient'sbody when the device is implanted in the patient's body. Similarly, theaccumulator may comprise coupling elements for conductive and/orwireless energy supply to the at least one motor of the infusion device.

A feedback subsystem, which may be part of a control unit describedbelow, can advantageously be provided to wirelessly send feedbackinformation relating to the energy to be stored in the energy storagemeans from inside the human body to the outside thereof. The feedbackinformation is then used for adjusting the amount of wireless energytransmitted by the energy transmitter. Such feedback information mayrelate to an energy balance which is defined as the balance between anamount of wireless energy received inside the human body and an amountof energy consumed by the at least one energy consuming part.Alternatively, the feedback information may relate to an energy balancewhich is defined as the balance between a rate of wireless energyreceived inside the human body and a rate of energy consumed by the atleast one energy consuming part.

Preferably, a control unit is provided for controlling an amount ofinfusion liquid to be administered through the at least one injectionneedle. A single command from the patient to the control unit, such as asingle actuation of a press button or other type of switch, issufficient for causing the control unit to control the injection of thedrugs at two different locations within the patient's body. The controlunit may be provided for controlling at least one of the pump, the driveunit and the motor and any other energy consuming part of the systemand, where the system includes an internal or external energy source,said energy source. Again, the control unit is preferably separate fromthe housing accommodating the infusion needle or needles so as to beimplantable within the patient's body. The control unit may be adjustedsuch that the appropriate amount of drugs will be administered at theappropriate time to the particular one of the injection sites. Automaticadministration will substantially relieve the patient.

Preferably, the control unit has a data transfer port for data transferbetween an external data processing device outside the patient's bodyand the control unit implanted in the patient's body, regardless ofwhether the control unit is contained in the housing accommodating theinfusion needle or needles or whether it is implanted within thepatient's body remote from said housing. The data transfer port allowsfor monitoring the control unit to adapt the system to changing needs ofthe patient. Preferably, the data transfer port is a wireless transferport for the data transfer, so as to provide easy data exchange betweenthe control unit and the external data processing device, e.g. during avisit to the doctor. Most preferably, the control unit is programmableto further increase its adaption flexibility. Instead of or in additionto the external data processing device, the control unit may comprise anexternal component for manual operation by the patient for setting intooperation the control unit.

Apart from or as a part of the control unit, feedback may be provided onparameters relevant for the treatment. Such parameters may be eitherphysical parameters of the patient and/or process parameters of thesystem. For this purpose, at least one feedback sensor is provided fordetecting such parameters. For instance, the feedback sensor may beadapted to detect one or more parameters relating to any of thefollowing: drug level, flow volume in blood vessel, pressure, electricalparameters, distension, distance, etc.

The feedback sensors may be connected to the control unit and thecontrol unit may comprise a control program for controlling drugdelivery in response to one or more signals from the feedback sensors.In addition or alternatively, feedback data may be transferred from thecontrol unit to the external data processing device. Such feedback datamay be useful for the doctor's diagnosis.

The penetration areas of the wall or walls of the housing or housingswithin which the infusion needle or needles are disposed may be arrangedin the patient's body at various locations. For instance, they may bearranged adjacent the left and right corpora cavernosa and/or the twodeep arteries running through the left and right corpora cavernosaand/or muscle tissue regulating blood flow through the patient's leftand right corpora cavernosa and/or another kind of tissue in closeproximity to the left and right corpora cavernosa.

A holder may be used to secure the corpora cavernosa to the housing orhousings so that the housing rests in place.

Other components of the system are preferably remotely implanted, suchas adjacent the patient's symphyseal bone. As discussed above, somecomponents of the system may be implanted subcutaneously. Subcutaneousimplantation increases the possibilities of wireless energy and/or datatransfer between the implanted and the extracorporal parts of thesystem. Also, refilling the reservoir through an injection port by meansof a replenishing needle penetrating through the patient's skin issubstantially facilitated when an injection port of the reservoir isimplanted subcutaneously. In particular, the compartment of thereservoir containing the saline solution might need to be refilledfrequently, whereas the other compartments comprising individual smalldoses of the drug would need no refill. It should be understood,however, that depending upon the circumstances any implantable componentof the system may be placed in the abdomen or even in the thorax.Activating means for direct manual operation by the patient may also beprovided to be implanted subcutaneously, e.g. for setting into operationone or more of the aforementioned motors or for simply setting intooperation the control unit of the system. Such activating means may bein the form of a subcutaneously implantable switch manually operable bythe patient from outside the patient's body.

The various aforementioned features of the invention may be combined inany way if such combination is not clearly contradictory. The inventionwill now be described in more detail in respect of preferred embodimentsand with reference to the accompanying drawings. Again, individualfeatures of the various embodiments may be combined or exchanged unlesssuch combination or exchange is clearly contradictory to the overallfunction of the device. In particular, while the following descriptionof preferred embodiments specifically relates to the stimulation ofpenis erection and, more specifically, to systems for the drug deliveryat two or more different injection sites, it is to be understood thatother uses, in particular with a single needle adapted for drug deliveryin a single injection site, are also encompassed by this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the muscles of the perineum,

FIG. 2 shows a cross-section through the penis,

FIG. 3 shows a first embodiment including a single needle,

FIG. 4 shows a second embodiment including a single needle and a motoraccommodated in a common housing,

FIG. 5 shows a third embodiment including two needles in a commonhousing,

FIG. 6 shows a plan view of a part of the infusion device of FIGS. 4 and5,

FIG. 7 shows a cross-sectional view through a penetration membrane madefrom a composite material,

FIG. 8 shows a cross-sectional view through the outer wall with flaps inthe penetration area,

FIG. 9 shows a cross-sectional view through the outer wall with anactively openable door in the penetration area,

FIG. 10 shows a cross-sectional view through the outer wall with anactively openable door according to another embodiment,

FIG. 11 shows a fourth embodiment including a plurality of needleswithin a common housing,

FIG. 12 shows a fifth embodiment comprising a single needle which islaterally and vertically displaceable,

FIG. 13 shows a sixth embodiment similar to the fifth embodiment, butwith more steps for laterally displacing the needle,

FIG. 14 shows a seventh, spherical embodiment for obtaining athree-dimensional array of penetration sites,

FIG. 15 shows an eighth embodiment comprising two needles in a commonhousing which are laterally and vertically displaceable,

FIG. 16 shows a ninth embodiment with a principle of advancing andretracting an infusion needle by means of a pull wire,

FIG. 17 shows a tenth embodiment with a principle of laterallydisplacing an infusion needle by means of pull wires,

FIG. 18 shows an eleventh embodiment with a principle of advancing andretracting a needle and laterally displacing a needle by means ofrotating shafts,

FIG. 19 shows the overall system of the invention implanted in apatient's body according to a first variation,

FIG. 20 shows the overall system of the invention implanted in thepatient's body according to a second variation,

FIG. 21 shows the overall system of the invention implanted in thepatient's body according to a third variation,

FIG. 22 shows drug compartments as part of the reservoir of the systemaccording to a first principle,

FIG. 23 shows drug compartments mounted on a tape wound on a reel in areplaceable cassette as part of the reservoir of the system according toa second principle,

FIG. 24 shows a part of the tape of FIG. 19 in greater detail,

FIG. 25 shows the principle of operation of the replaceable cassette ofFIG. 23,

FIG. 26 shows drug compartments as part of the reservoir of the systemaccording to a third principle,

FIG. 27 shows a cross-sectional view through the drug compartments ofFIG. 26 including an insulation chamber and cooling device,

FIG. 28 shows the principle of the cooling device of FIG. 27 incombination with a heat exchanger,

FIG. 29 shows a specific embodiment for the cooling device of FIG. 27,

FIG. 30 shows a part of the system implanted in the patient's bodycomprising separate needles for the right and the left corpuscavernosum,

FIG. 31 diagrammatically shows the system of FIG. 30,

FIG. 32 shows a part of the system of FIG. 31, including a tube intowhich the needle can be advanced,

FIGS. 33A to 33C show a first and second embodiment forelectromagnetically displacing the infusion needle in a plurality oflateral directions, and

FIGS. 34A and 34B show a third embodiment for electromagneticallydisplacing the infusion needle in a plurality of lateral directions.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the muscles of the perineum of a male. Reference numerals1, 2 and 3 designate the ischiocavernosus muscles, bulbospongiosusmuscles and superficial transverse perineal muscles, respectively. Thebulbospongiosus muscle surrounds lateral aspects of the bulb of thepenis at the most proximal part of the body of the penis inserting intothe perineal membrane, and further surrounds the dorsal aspect of thecorpus spongiosum 4 surrounding the urethra 5 and the left and rightcorpora cavernosa 6, 7. The ischiocavernosus 1 embraces the crus of thepenis, inserting onto the inferior and medial aspects of the crus and tothe perineal membrane medial to the crus. While the bulbospongiosusmuscle assists the erection by compressing outflow via the deep perinealvein and by pushing blood from the bulb into the body of the penis, theischiocavernosus muscle 1 maintains erection of the penis by compressingoutflow veins and pushing blood from the root of the penis into the bodyof the penis. FIG. 2 is a cross-sectional view through the penis. As canbe seen, the penis is composed of three cylindrical bodies of erectilecavernous tissue: the paired corpora cavernosa 6, 7 dorsally and thesingle corpus spongiosum ventrally. Deep arteries 9, 10 run distallynear the center of the corpora cavernosa, supplying the erectile tissuein these structures. The deep arteries of the penis are the main vesselsof the cavernous spaces in the erectile tissue of the corpora cavernosaand are therefore involved in the erection of the penis. They give offnumerous branches that open directly into the cavernous spaces. When thepenis is flaccid, these arteries are coiled, restricting blood flow.

For reasons of simplification, the following figures only display thecorpora cavernosa 6, 7. FIG. 3 shows a part of the system according to afirst embodiment. More specifically, a single infusion needle 11 isarranged in a housing 12 with a tip end 13 of the needle 11 beingpositioned such that it can be advanced and retracted through aself-sealing window area 14 in the housing's 12 outer wall 15 in alongitudinal direction 16, so as to pierce the corpus cavernosum 6 or 7located adjacent the window area 14.

Two window areas 14 are provided in the outer wall 15 of the housing 12,one adjacent each of the two corpora cavernosa 6, 7. The infusion needleis displaceable in a lateral direction 17 between the two window areas14 by means of a drive unit D. The same drive unit D or a differentdrive unit may cause the infusion needle 11 to be advanced andretracted. For this purpose, the infusion needle 11 is mounted on aslide 18 for longitudinal advancement and retraction. A conduit 19 isconnected to one end of the infusion needle 11 to supply infusion liquidthrough the infusion needle 11 to the tip end 13 thereof.

In operation, the infusion needle 11 will first be advanced with the tipend 13 thereof to penetrate one of the two self-sealing penetrationwindows 14, injection fluid containing a drug for stimulation of peniserection will be injected into the corpus cavernosum 7 through theinfusion needle 11 and, thereafter, the infusion needle 11 will beretracted again. Upon retraction of the infusion needle, the infusionneedle will be laterally displaced along the direction 17 so that thetip end 13 thereof comes to lie in front of the other of the twoself-sealing window areas 14, the infusion needle 11 will be advancedagain so that infusion liquid can be injected through the tip end 13thereof into the other corpus cavernosum 7 and then the infusion needle11 will be retracted again. At the end of this procedure, the infusionneedle 11 will return to its initial position shown in FIG. 3.

The structure of the system shown in FIG. 3 may be purely mechanical.For instance, as will be described in more detail below, the pressurewith which the infusion liquid is advanced through the conduit 19towards the needle 11 may in cooperation with spring elements cause theneedle 11 to be advanced, retracted and laterally displaced to the otherwindow area 14. Thus, after two pulses of injection fluid advancedthrough the conduit 19 towards the needle 11, the needle 11 willautomatically return to its starting position shown in FIG. 3.

However, it is likewise possible to incorporate a motor M or a pluralityof motors M within the housing 15 in order to achieve the desired needledisplacement by means of the drive unit D. This is schematically shownin FIG. 4. Of course, the motor M will have to be provided with energyand will need to be controlled in an appropriate manner so as to obtainthe desired effect. This is not specifically shown in FIG. 4. The energyis preferably transmitted to the motor M from an energy source eitherremotely implanted inside the patient's body or provided externally ofthe patient's body.

The drive D may be configured such that after each penetration cycle(consisting of two injections) the infusion needle 11 stops at aposition different from the starting position so that the tip end 13thereof penetrates the window areas 14 in the next following injectioncycle at different sites as compared to the foregoing injection cycle.

FIG. 5 shows a third embodiment which differs from the first and secondembodiments in that it comprises two infusion needles 11 contained inthe housing 15. Thus, when infusion liquid is guided through the conduit19 towards the two infusion needles 11, both needles are advanced andretracted simultaneously along the direction 16, so that injection ofinfusion liquid occurs at exactly the same time. The drive unit D or aseparate drive unit may be used to turn the turntable 20 on which theinfusion needles 11 are mounted, stepwise in the direction 17 so thatthe window areas 14 will be penetrated by the tip end of the infusionneedle 11 at different penetration sites during the next followinginjection cycle. Again, one or more motors M, not shown in FIG. 5, maybe used for driving one or more of the components of the drive unit D.

The principle of a guide structure for laterally displacing the infusionneedle will now be described in context with FIG. 6. Such guidestructure may be used e.g. for each of the two infusion needles 11 shownin FIG. 5 or may also be used slightly modified for the lateraldisplacement of the infusion needle 11 shown in FIGS. 3 and 4.

The guide structure 28 is securely fixed adjacent the self-sealingwindow area 14 which itself is implanted adjacent the patient's corpuscavernosum 7. The guide structure 28 comprises a guide pin 27 securelyconnected to the infusion needle 11 (not shown) such that the infusionneedle 11 cooperates with the guide structure 28. Upon advancement orretraction of the infusion needle 11, the guide pin 27 will be guided inthe guide structure 28 and thereby laterally displace the infusionneedle 11, which lateral displacement causes rotation of the turntable20 (not shown in FIG. 6). Resilient flaps 28 a, 28 b within the guidestructure 28 serve to guide the guide pin 27 through the entire guidestructure 28 upon repeated advancement and retraction of the infusionneedle 11. The guide structure 28 is designed to provide differentpenetration sites through the self-sealing window area 14 into thecorpus cavernosum 7. Where it is desired, the trajectory of guidestructure 28 may include a return path 28 c for the guide pin 27 toreturn to its starting position shown in FIG. 6. Such return action willbe caused by a return spring 29 which is permanently fixed to a rigidpart of the housing 15.

The same structure can likewise be used in the embodiments shown inFIGS. 3 and 4 to displace the single infusion needle 11 laterallybetween the two window areas 14. Of course, the structure would have tobe slightly adapted to accommodate for the larger distance to beovercome between the two window areas 14.

FIG. 7 shows a preferred embodiment of a penetration membrane to be usedas the self-sealing window area 14 in the outer wall 15 of the housing12. The penetration membrane 30 is made from a composite material. Thesame material can also be used for other flexible wall portions or foran infusion port that will be described below in connection with anotherembodiment. The composite material of penetration membrane 30 shown inFIG. 7 comprises an outer shape-giving layer 30 a defining a volume inwhich a self-sealing soft material 30 b is contained. Self-sealing softmaterial 30 b can be of gel type having a viscosity such that it doesnot flow through any penetrations caused by the infusion needle 11during penetration of the outer shape-giving layer 30 a. Instead of asingle outer shape-giving layer 30 a, the shape-giving layer 30 a maycomprise a plurality of layers. The outer shape-giving layer 30 apreferably comprises silicone and/or polyurethane, since such materialscan be produced to have self-sealing properties in respect ofpenetrations resulting from the infusion needle 11.

Instead of a self-sealing membrane, the window area 14 in the outer wall15 of the housing 12 may be formed by one or more flaps, as shown inFIG. 8. Two flaps 30′ being made from a resilient, biocompatiblematerial are arranged so as to form a slit which is normally closed andthrough which the infusion needle 11 can pass when it is advanced. Uponadvancement of the infusion needle 11, the needle will push aside thenormally closed flaps 30′, and when the needle 11 is retracted again,the flaps 30′ will return to their normally closed position so as toform a seal against ingression of body liquid.

FIG. 9 shows a different embodiment. In this case, the self-sealingwindow 14 in the outer wall 15 comprises a door 30″ which can be openedby mechanical action. In the embodiment shown, the door is formed by aflap made from a resilient, biocompatible material which keeps thewindow area 14 closed in its normal position. A pull wire 300 isattached to one end of the door 30″ in order to allow for opening thedoor by pulling the pull wire 300. The pull wire 300 or any other driveconnected to the door 30″ forms part of the drive unit coupled to theinfusion needle 11. For instance, as is shown in FIG. 10, the pull wire300 may be attached directly to the infusion needle 11 so thatadvancement of the infusion needle 11 will simultaneously cause the door30″ to be lifted up so that the infusion needle 11 can pass underneaththe door 30″ and thus penetrate the outer wall 15 easily. Due to theresiliency of the door material, the door 30″ will automatically closewhen the force, such as the pulling force exerted via the pull wire 300,is released. Instead or in addition, the closing action may be supportedby at least one spring element urging the door into its closed position.

FIG. 11 shows a fourth embodiment comprising a plurality of infusionneedles for each of the two window areas 14. In this embodiment it isnot necessary to provide a turntable by which the needles can be pivotedstepwise in order to laterally displace the needles from one penetrationsite to a different penetration site within the same window area 14.Instead, upon successive injection cycles a different one of theplurality of injection needles will be advanced and retracted for eachof the two window areas 14. Thus, the effect achieved is the same as inthe embodiment shown in FIG. 5. However, instead of the turntable 20(FIG. 5) a valve V is needed to direct the infusion liquid to only oneof the plurality of infusion needles 11 in each of the two window areas14. More specifically, depending upon the position of the valve V, afirst one of the infusion needles 11 in the first window area 14 and afirst one of the plurality of the infusion needles 11 in the secondwindow area 14 will be advanced and retracted simultaneously, and duringthe next following infusion cycle, another one of the plurality ofinfusion needles will be advanced and retracted in the two window areas14.

FIG. 12 shows a fifth embodiment which differs from the first and secondembodiments shown in FIGS. 3 and 4 in that the single infusion needle 11is not only laterally displaceable in the direction 17 between the twowindow areas 14 but also laterally displaceable between differentpenetration sites 21 within the same penetration area 14. Morespecifically, the direction of lateral displacement of the tip end ofthe infusion needle 11 within each of said different penetration areas14 is perpendicular to the direction of lateral displacement between thedifferent penetration areas 14. To achieve this result, the drive unit Dis configured to longitudinally advance and retract the infusion needle11 along a direction 16, to pivot the infusion needle 11 by means of aturntable 20 between the two penetration areas 14 along a pivotingdirection 17 and to raise or lower the infusion needle 11 along a thirddirection 22 perpendicular to the longitudinal direction 16. A suitablepurely mechanical construction may perform this function. However, oneor more motors may also be provided to perform one and/or the other ofthese functions.

FIG. 13 shows a sixth embodiment similar to the fifth embodiment shownin FIG. 12. In contrast to FIG. 12, the infusion needle 11 is not onlylaterally displaceable between different penetration sites 21 within thesame penetration area 14 in a direction perpendicular to the directionof lateral displacement between the two penetration areas 14, but isalso laterally displaceable within the same penetration area 14 in adirection parallel to the direction of lateral displacement between thedifferent penetration areas 14. In other words, the tip end of theinfusion needle 11 is laterally displaceable in two dimensions withinthe same penetration area 14.

FIG. 14 shows a seventh embodiment which enables the infusion needle 11to be moved along a three-dimensional, spherically curved array ofpenetration sites. In this embodiment, a part of the housing 12, morespecifically the window area 14, is spherically curved and the needle 11is mounted in a sphere so that upon rotation of the sphere along thedirections 17 a and 17 b the tip end 13 of the needle 11 can be moved toany position in front of the window area 14. Once an appropriateposition has been adjusted for the tip end 13, the needle 11 can beadvanced on the slide 18 so as to penetrate the window area 14. Insteadof accommodating the slide inside the sphere, it may likewise be mountedon the outer surface of the sphere. Similarly, the infusion needle 11itself can be mounted on the outer surface of the sphere. The mechanismfor moving the sphere along the directions 17 a, 17 b can be of manydifferent types, such as mechanical by means of rollers or magnetic.

FIG. 15 shows an eighth embodiment similar to the third embodiment shownin FIG. 5. That is, two needles 11 are provided in a common housing soas to be longitudinally movable in order to advance and retract the tipends thereof through the penetration areas 14. Instead of mounting theinfusion needles 11 on a turntable 20, as in the embodiment of FIG. 5,so as to change the injection sites 22 within a penetration area 14 uponeach injection cycle, the eighth embodiment of FIG. 15 achieves the sameresult by raising and lowering the two injection needles along adirection 22, similar to the fifth embodiment described above inrelation to FIG. 12. Again, the result is that the direction of lateraldisplacement of the tip ends of the two infusion needles 11 within eachof the two different penetration areas 14 is perpendicular to thedirection of distance between the two different penetration areas 14. Ofcourse, this embodiment, like the sixth embodiment shown in FIG. 13, canalso be modified such that the tip ends of the two infusion needles 11are laterally displaceable in two dimensions within the same penetrationarea 14.

FIG. 16 shows a ninth embodiment with a principle of advancing andretracting the infusion needle 11 by means of a pull wire 101. The pullwire 101 is redirected about a pin 102 such that by pulling the wire 101at an end remotely located somewhere in the patient's body the tip endof the infusion needle 11 will be advanced through the window of thehousing 12. A helical spring provides a counterforce so that theinfusion needle 11 will be retracted once the pulling force on the pullwire 101 is released. This principle can be combined with otherembodiments described hereinbefore and hereinafter. Instead of thehelical spring 104, a second pull wire may be provided to retract theinfusion needle 11. It is even possible to use a single pull wire 101running around two pins 102 in a loop, so that pulling the wire 101 inthe one direction or in the other direction will cause advancement orretraction of the infusion needle 11.

The pull wire 101 and the conduit 19 for the infusion liquid are guidedin a common sheath 103. The common sheath 103 has various functions.First, it gives support to the pull wire 101 in bending sections.Second, it facilitates implantation of the conduit 19 along with thepull wire 101. Third, it protects the pull wire 101 against any build-upof fibrosis.

FIG. 17 shows a tenth embodiment which involves remotely actuated pullwires 105, 106 guided within a common sheath 103 along with the conduit19 for the infusion liquid. The pull wires 105 and 106 are directlyattached to the infusion needle 11 on opposite sides thereof so that theinfusion needle 11 which is mounted on a turntable 20 will be laterallydisplaced in the one direction or in the other direction depending onwhether the wire 105 or the wire 106 is pulled. Instead of using twowires 105, 106, one of the wires may be replaced with a pretensioningmeans, such as the helical spring 104 in FIG. 16. In addition, a furtherwire, in particular third wire (not shown), may be provided for lateraldisplacement of the infusion needle 11 in a further direction, so that atwo-dimensional lateral displacement can be achieved by pulling theappropriate wires.

The pull wires may alternatively be attached to an element other thanthe infusion needle 11, provided that the infusion needle 11 isconnected to such other element, so that when the other element is movedor turned by pulling one or more of the wires the tip end of theinfusion needle 11 will be displaced accordingly.

In the case that a long, flexibly bendable needle is provided with thetip end thereof being arranged in a first housing for penetrating theouter wall of the first housing and the other end is arranged in aremotely implanted second housing, one can dispense with the turntable20 and achieve accurate lateral displacement of the tip end of theneedle by pulling the appropriate one of three pull wires which areattached either directly or indirectly to the circumference of the frontend of the infusion needle at regularly spaced intervals.

FIG. 18 shows an eleventh embodiment with a different principle ofadvancing and retracting the tip end of the infusion needle, on the onehand, and laterally displacing the tip end of the infusion needle 11, onthe other hand. Instead of pull wires, rotating shafts 107, 108 areprovided. The drive for driving the rotating shafts 107, 108 is remotelylocated somewhere in the patient's body. The front ends of the rotatingshafts have a threading 109, 110, e.g. in the form of a worm screw,meshing with the teeth of a rack 111, 112 formed either directly orindirectly on the infusion needle 11 and on the turntable 20,respectively. Thus, by turning the rotating shaft 107, the infusionneedle 11 will advance or retract, as the case may be, due to thecooperation of the worm screw 109 and the rack 111. Similarly, byturning the rotating shaft 108, the infusion needle 11 will be displacedlaterally in the one or the other direction due to the cooperation ofthe worm screw 110 and the rack 112 of the turntable 20. Again, therotating shafts 107, 108 are guided in a common sheath 103 along withthe conduit 119 for the infusion liquid.

In FIGS. 17 and 18, the action of the pull wires 105, 106 and therotating shaft 108 make it possible to laterally displace the tip end ofthe infusion needle 11 between two different penetration areas and/orfrom a first penetration site to a second penetration site within asingle penetration area.

FIG. 19 shows a first variation of an overall system comprising any oneof the first to eleventh embodiments described above. Specifically shownin the variation shown in FIG. 19 is a housing 12 with a single infusionneedle 11 and a drive unit D as described in relation to FIG. 12. Thehousing 12 is implanted with its windows areas 14 positioned adjacentthe corpora cavernosa 6, 7, of which window areas 14 only one is shownin FIG. 19. A motor M is contained in the housing 12 for driving thedrive unit D. The motor M within the housing 12 is controlled by meansof a control unit C₂ constituting the implantable part of a controlsystem which further comprises an external data processing device C₁ bywhich commands and any other kind of data can be sent to the controlunit C₂. For instance, the external data processing device C₁ may beused to initiate an injection cycle from outside the patient's body,this being done wirelessly as indicated by arrow 23. The implantedcontrol unit C₂ not only controls the motor M inside the housing 12 butalso controls the energy supply from an accumulator A to the motor Minside the housing 12.

The external data processing device C₁ may likewise be used to programthe implanted control unit C₂. Also, a data transfer port fortransferring data between the external data processing device C₁ and theimplanted control unit C₂ may be adapted to transfer data in bothdirections.

A feedback sensor F implanted inside the patient's penis is shown hereas being connected to the motor M inside the housing 12 and may likewisebe connected to the implantable control unit C₂. The feedback sensor Fcan sense one or more physical parameters of the patient, such as thedrug level inside the corpora cavernosa, the flow volume through thecorpora cavernosa, the pressure inside the corpora cavernosa and thelike. Other feedback sensors may be provided at a different location soas to sense process parameters of the system, such as electricalparameters, distention, distance and the like.

The conduit 19 connecting the needle 11 with a reservoir comprisingcompartments R₁ and R₂ and the wiring 24 for transmitting electricenergy from the energy source A to the motor M inside the housing 12 areguided through a common conduit 25.

In the variation of the entire system shown in FIG. 19, the reservoircomprises a first compartment R₁ with e.g. a saline solution includedtherein, and a second compartment R₂ with e.g. a drug in powder form orfreeze-dried form included therein. A pump P driven by a second motor M₂is arranged to pump infusion liquid from the reservoir R₁ to theinfusion needle 11. The infusion liquid pumped by the pump P will passthrough a mixing chamber 26 into which drugs will be released from thereservoir R₂ in appropriate time coordination. The motor M₂ or adifferent motor may cause the drugs to be released from the secondreservoir R₂. The motor M₂ is also controlled by the control unit C₂.Thus, infusion liquid pumped via the pump P from the relatively largefirst reservoir R₁ through the mixing chamber 26, in which it is mixedwith the drugs released from the second reservoir R₂, will reach theinfusion needle 11 which has meanwhile penetrated the self-sealingwindow area 14 of the housing 12 and will flow into the corpuscavernosum 7.

In addition to or instead of the control unit C₂, a pressure sensitiveswitch for activating the motor M inside the housing 12 and/or the motorM₂ may be arranged subcutaneously.

Although the embodiment shown in FIG. 19 may comprise one of a greatvariety of reservoir types, a particular reservoir type will now bedescribed. The volume of the reservoir R₁ is divided into two sectionsby means of a membrane 31. One section is filled with gas whereas theother section is filled with the infusion liquid (saline solution). Aninfusion port 32 allows for refilling the reservoir R₁ with infusionliquid by means of a replenishing needle. When the reservoir R₁ is inits full state, the gas section is at ambient pressure orover-pressurized. As infusion liquid is drawn from the reservoir R₁ bymeans of the pump P upon each infusion cycle, the pressure in the gassection will decrease below ambient pressure, i.e. to a negativerelative value. Depending upon the particular type of pump P, it may beadvantageous to provide a single acting ball valve to prevent anybackflow from the pump P to the reservoir R₁.

There are various ways of providing the motors M and M₂ with energy. Inthe variation shown in FIG. 19, energy is supplied from outside thepatient's body either for direct use by the motors and/or for chargingthe accumulator A, which may be in the form of a rechargeable batteryand/or a capacitor. An extracorporal primary energy source E transmitsenergy of a first form through the patient's skin 100 to an energytransforming device T which transforms the energy of the first form intoenergy of a second form, such as electric energy. The electric energy isused to recharge the accumulator A which provides secondary energy tothe motor M upon demand.

The external primary energy source E may be adapted to create anexternal field, such as an electromagnetic field, magnetic field orelectrical field, or create a wave signal, such as an electromagneticwave or sound wave signal. For instance, the energy transforming deviceT as shown in FIG. 19 may act as a solar cell, but adapted to theparticular type of wave signal of the primary energy source E. Theenergy transforming device T may also be adapted to transformtemperature changes into electrical energy.

Instead of the external primary energy source E, an implantable primaryenergy source E may be used, such as a regular long-life battery insteadof the accumulator A.

The energy signal may also be used to transmit signals from the externaldata processing device C₁ by appropriate modulation of the energysignal, regardless of whether the energy is transmitted wirelessly or bywire, the energy signal thereby serving as a carrier wave signal for thedigital or analog control signal. More particularly, the control signalmay be a frequency, phase and/or amplitude modulated signal.

FIG. 20 shows a second variation of the entire system which basicallydiffers from the system of FIG. 19 only in that the motor M inside thehousing 12 is dispensed with. Instead, the motor M₂ is used to drive thedrive unit D. This is achieved by means of a rotating shaft 33 in theform of an elastically bendable worm screw, the rotating shaft 30replacing the wiring 24 of the system shown in FIG. 19.

FIG. 21 shows a third variation of the entire system which operatespurely mechanically. The reservoir R₁ containing the infusion liquid,i.e. the saline solution, is of balloon type, thereby functioning bothas a reservoir and as a pump if it is compressed manually from outsidethe patient's body. The pressure generated in the reservoir R₁ will acton the reservoir R₂ containing the drug. Upon a certain pressure, thedrug will be released from the reservoir R₂ into the mixing chamber 26and upon further increase of the pressure the infusion liquid will beallowed to enter the mixing chamber 26, mix with the drug released fromthe reservoir R₂, flow towards the infusion needle 11, and build uppressure in the infusion needle 11 such that the drive unit D is causedto advance the infusion needle 11 through the self-sealing window area14 into the patient's corpus cavernosum. Once the pressure is released,the infusion needle 11 will retract automatically due to mechanicalspring forces or the like and move into a different position in which itcan penetrate the second of the two self-sealing window areas 14 whenthe reservoir R₁ is compressed again. Where two infusion needles 11 areprovided in the housing 12, a single compressing action on the reservoirR₁ would be sufficient to inject the drug into both the left and rightcorpora cavernosa.

FIG. 22 shows a first principle of how drugs within a plurality ofcompartments 34 of the reservoir R₂ can be released one at a time by apurely hydromechanical solution. As the infusion liquid is urged fromthe reservoir R₁ towards the conduit 19 leading to the infusion needleor needles, it is first blocked by a spring-loaded ball valve 34 whichopens only when a certain pressure is exceeded. The pressure building upin front of the ball valve 34 is guided by means of a stepper valve Vsequentially onto one of a plurality of compartments 35. Thecompartments are each formed as a cavity 35 within a piston 36. Once acertain pressure is exceeded, the piston 36 will be pushed into aposition where the compartment 35 is in flow communication with a mixingchamber 26. In the state shown in FIG. 22, three pistons 36 have alreadybeen pushed into such position. When the pressure in the reservoir R₁ isfurther increased, the spring force of the ball valve 34 will beovercome and the infusion liquid urged from the reservoir R₁ towards theconduit 19 will take with it the drug that has been released into themixing chamber 26.

FIGS. 23 to 25 show a second principle of realizing the reservoir R₂comprising a plurality of small drug compartments 35, 35 a, 35 b. Thedrug compartments are integrally formed in a tape 201 which is wound ona first reel 202 and can be unwound from said first reel 202 onto asecond reel 203. The reels 202, 203 and the tape 201 are contained in acassette 200 which may be inserted in the entire system so as to formpart of the reservoir. The cassette 200 is preferably replaceable.

As can be seen in FIG. 24, the compartments 35, 35 a, 35 b containingthe drug e.g. in powder form or freeze-dried form are arranged in aplurality of rows as seen in the transporting direction (indicated bythe arrow). However, the compartments 35 of one row are a certaindistance offset in the transporting direction from the compartments 35 aand 35 b of the other rows. Thus, when the tape 201 is wound from reel202 to reel 203, it is guided through a conduit 204 forming part of thecassette 200 through which the infusion liquid is pumped from thereservoir R₁ to the infusion needle or needles, and the compartments 35,35 a, 35 b will enter the conduit 204 one after the other.

While it is conceivable to open one of the compartments 35, 35 a, 35 bthat has entered the conduit 204 by mechanical action, such as a hammeror piercing element, the opening of the compartments 35 in theembodiment shown in FIGS. 23 to 25 needs no further action other thanwinding the tape 201 onto the reel 203. That is, as can be seen fromFIG. 25, when the tape 201 enters the conduit 204 through a first slit205, the compartments 35 will not be damaged due to the fact that theslit 205 is relatively wide and is closed by two soft sealing lips 206.However, when the tape 201 exits the conduit 204 on the other sidethereof, it will have to pass a narrower second slit 207 with frontedges 208 that are not resilient. The compartments 35 will thereforeburst on their way out of the conduit 204 when they slip between theedges 208 of the narrow slit 207. Soft seals 209 in the slit 207 preventliquid from leaking from the conduit 204.

The entry 210 and the exit 211 of the conduit 204 within the cassette200 each include a valve that automatically closes when the cassette 200is removed from the system and automatically opens when the cassette 200is installed in the system. This allows for replacement of the cassette200 without adversely affecting the remaining components of the overallsystem.

FIGS. 26 and 27 show a third principle of realizing the reservoir R₂comprising a plurality of small drug compartments 35. While FIG. 26shows a cross-sectional plan view according to section BB in FIG. 27,FIG. 27 shows a cross-sectional side view thereof according to sectionAA in FIG. 26. The compartments 35 containing the drug in powder form orfreeze-dried form are arranged in a rotatable plate 37. A motor M₂ isprovided to rotate the plate 37 about an axis 38. The motor M₂ iscontrolled to advance the plate 37 stepwise so as to bring onecompartment 35 at a time in line with the conduit 39 connecting thereservoir R₁ containing the saline solution with the infusion needle orneedles. Energy is supplied to the motor M₂ from the accumulator A viathe control unit C₁.

The rotatable plate 37 is mounted in a fixed base plate 39 which itselfis fixedly mounted in a housing 40 insulating the base plate 39 and therotatable plate 37 thermally against an outer housing 42. A coolingdevice 41 is provided to cool a liquid surrounding the base plate 39 androtatable plate 37 down to a temperature below 37° C. This serves toprotect the drugs inside the compartment 36 from degrading too quickly.The accumulator A supplies the cooling device 41 with energy.

FIG. 28 shows a general principle of cooling the reservoir R₂ containingthe drug to be cooled. The cooling device 41 may be an electrothermalcooler, i.e. based on the Peltier effect consuming electric energy, ormay be of the refrigerator type. Accordingly, the cold part of thecooler 41 is placed on the side to be cooled whereas the warm part ofthe cooling device 41 is placed on the other side so that the heatenergy can be dissipated to the outside. An increased surface 41 a onthe warm side of the cooling device 41 serves to increase heatdissipation. Furthermore, a heat exchanging fluid may be passed througha conduit 41 b along the increased surface 41 a to transfer thedissipated heat energy to a remote location within the patient's bodywhere the heat is dissipated into the patient's body through a specificheat exchanging surface 41 c.

FIG. 29 shows a different principle of cooling the drugs contained inthe reservoir R₂. In this embodiment, two chemicals X1 and X2 arecontained separate from each other in respective compartments of thecooling device 41. When the chemicals X1 and X2 are brought together,they will react with each other and such reaction will consume energywhich is absorbed as thermal energy from the surroundings. By means oftwo pistons 41 d, 41 e, the chemicals X1, X2 are dispensed into acooling line 41 f in a controlled manner, which cooling line ispreferably in contact with the housing 40 containing the reservoir R₂.The chemical mixture X1-X2 displaced within the cooling line 41 f willflow back into the chamber containing the chemicals X1, X2, but onto theother side of the pistons 41 d, 41 e.

A further embodiment is shown in FIG. 30. In this embodiment, again, twoseparate needles are provided, one needle for each of the left and rightcorpora cavernosa. However, unlike the previously discussed embodiments,the two needles each have their own housing 12 implanted in thepatient's body with their respective self-sealing window area 14adjacent the left and right corpora cavernosa, respectively. Thisprinciple is shown in FIG. 31 in more detail with respect to one of thetwo needles. The drive unit D comprises a piston 50, to which the hollowinfusion needle 11 is attached. The piston 50 separates a first chamber51 a in front of the piston 50 and a second chamber 51 b behind thepiston 50. While the pressure in the first chamber 51 a corresponds tothe pressure exerted by the pump P, the pressure in the second chamber51 b can be kept at a lower value. The second chamber 51 b may be filledwith a liquid, such as the infusion liquid, and the liquid may be urgedinto a flexible volume 52. The flexible volume 52 could be of simpleballoon type so as to fill up without exerting any strong counterforce.

Instead of the flexible volume 52, a conduit 53 may connect the secondchamber 51 b with the reservoir R₁. Thus, when the needle 11 isadvanced, liquid will be dispelled from the second chamber 51 b throughthe conduit 53 into the reservoir R₁, and as the needle 11 is retractedby means of a return spring 55, liquid will be drawn from the reservoirR₁ through the conduit 53 back into the second chamber 51 b.

The injection process is carried out as follows. As the pressure isincreased in the first chamber 51 a by means of the pump P, the needle11 will be displaced against the force of the spring 55 of the driveunit B. Thus, the tip end 13 of the infusion needle 11 will penetratethrough the self-sealing window area 14 press-fitted into the wall 15 ofthe housing 12 and will further penetrate any fibrosis having built upin front of the housing. When the return spring 55 is completelycompressed and the pressure built up by the pump P is further increased,a ball valve 56 will be displaced against a second return spring 57which is stronger than the first return spring 55. That way, as long asthe pressure is held at a sufficiently high level, infusion liquid willbe pumped from the reservoir A₁ through the conduit 19, the hollowinfusion needle 11 and the needle's laterally arranged exit port intothe patient's body. Upon pressure release, the ball valve 56 will closedue to the return springs 55 and 57, and then the needle 11 will beretracted to its initial position shown in FIG. 22.

It may be advantageous not to pierce any living tissue by means of theinjection needle 11 once it is advanced through the outer wall 15 of thehousing 12. Therefore, as shown in FIG. 32, a tube 58 may be placed infront of the window area 14. The cross-sectional form of the tube 58 maybe adapted to the cross-sectional form of the window area 14, i.e. wherethe window area 14 is rectangular, the tube 58 likewise has arectangular cross-section.

The exit end of the tube 58 has an open area 59 sufficiently large toprevent growth of fibrosis from spanning over the open area. Fibrosiswill slowly grow into the tube along the tube's inner surface, before itreaches the window area 14 after a relatively long time. The tip end 13of the needle 11 will therefore not have to penetrate any fibrosisduring the first while after implantation of the system. Preferably, theopen area 59 has an opening width of at least 3 mm. The length of thetube 58 may be in the range of 4 mm to 30 mm. The opening width 59 andthe length of the tube 58 should be adjusted such that the substanceinjected into the tube 58 can safely seep into the patient's body. Thus,the longer the tube is, the larger the opening width thereof should be.

FIGS. 33A and 33B show a first embodiment for displacing the tip end ofthe infusion needle 11 in two or more different directions, i.e. atwo-dimensional displacement. More specifically, FIG. 33A shows a planview, whereas FIG. 33B shows a side elevational view schematically. Ascan be seen, a plate 60 to which the infusion needle 11 is fixedlymounted has a projection 61 extending into a frame 62 within which theprojection 61 is free to move in any direction. Electromagnetic coils 63are mounted on the sides of the frame 62 and are individuallyenergizable. The electromagnetic coils 63 constitute the first part ofan electromagnetic drive whereas the projection 61 is configured toconstitute the second part of the electromagnetic drive. Thus, when oneor more of the electromagnetic coils are energized, an electromagneticfield is created in the frame 62 and the electromagnet second part, i.e.the projection 61, will adjust its position within such fieldaccordingly. Due to the fact that the infusion needle 11 is fixedlymounted to the plate 60, the infusion needle 11 will move along with theprojection 61. This way, the infusion needle 11 can be advanced andretracted and can also be displaced laterally.

Of course, the infusion needle 11 may be attached to the electromagneticdrive in a different manner, e.g. perpendicular to the plane defined bythe electromagnetic coils 63 (rather than in parallel as in FIG. 33B).As a result, the infusion needle would be laterally displaceable in aplurality of directions (rather than being advanceable and retractable).

Alternatively, the electromagnetic drive may be such as to displace theinfusion needle in any lateral direction and, in addition, to advanceand retract the infusion needle. This can be achieved e.g. with astructure as schematically shown in FIG. 33C relating to a secondembodiment for displacing the tip end of the infusion needle 11. FIG.33C shows an elevational side view similar to FIG. 33B, but theelectromagnetic coils 63 do not define a single plane, but rather aplurality of planes is defined one above the other by providingadditional electromagnetic coils 63 in a vertical direction. The topplan view would be similar to FIG. 33A. This way, the electromagnetsecond part 61 fixedly connected to the needle 11 moves within athree-dimensional frame 62 depending on the energization of respectiveones of the magnetic coils 63.

FIGS. 34A and 34B show a plan view and a side view of a third embodimentof an electromagnetic drive for moving the infusion needle 11 in aplurality of directions. In this embodiment, the electromagnetic coils63 constituting the electromagnet first parts are arranged in a firstplane and the electromagnet second part constituted by the protrusion 61fixedly connected to the infusion needle 11 via the plate 60 is movablein a plane in front of or behind the plane defined by the electromagnetfirst parts. However, the electromagnetic coils 63 are orienteddifferently in this third embodiment. Again, depending upon theenergization of the individual electromagnetic coils, the electromagnetsecond part, i.e. the protrusion 61, will adjust its position in thecreated electromagnetic field within the frame 62.

A method of treating a human being (or an animal) by implanting at leastpart of the system in the patient's body comprises the steps of cuttingthe skin, dissecting free a first area near the left and right corpuscavernosum, placing the at least one housing accommodating the at leastone infusion needle within said dissected area such that the tip end ofthe at least one infusion needle, when penetrating the housing's outerwall, can penetrate into the left and right corpus cavernosum and/or thetwo deep arteries of the right and left corpus cavernosum and/or intomuscle tissue regulating blood flow to the patient's left and rightcorpus cavernosum and/or into another kind of tissue in close proximityto the patient's left and right corpus cavernosum allowing stimulationof erection of the two corpora cavernosa, and finally closing at leastthe skin after implantation of at least parts of the system.

Where parts of the system are implanted remote from the corporacavernosa, a second area remote from the first area may be dissectedfree in order to place e.g. the at least one reservoir in the patient'sbody at the remote second area, with a conduit connecting the reservoirwith the at least one infusion needle accommodated in the at least onehousing. In this case, it is preferable to place the reservoir adjacentthe patient's symphyseal bone.

One or more of the following elements may be placed within the patient'sbody remote from the housing or housings accommodating the at least oneneedle:

-   -   at least one drive unit for advancing and retracting the tip end        of the infusion needle,    -   a pump (P) for advancing the substance from the reservoir to the        at least one infusion needle,    -   at least one motor (M, M₂) for actuation of the drive unit (D)        or a drive driving the drive unit, and/or the pump (P) and/or        any other energy consuming part of the system,    -   energy storage means (A) for providing the at least one motor        with energy,    -   galvanic coupling elements between either an external energy        source (E) or the energy storage means (A) and the motor (M, M₂)        for transmitting energy to the motor in contacting fashion,    -   wireless coupling elements adapted to connect either the motor        (M, M₂) or the energy storage means (A) or both to an        extracorporal primary energy source for transmitting energy to        either the motor or the energy storage means or both in        non-contacting fashion,    -   control unit (C1) for controlling the motor (M, M₂),    -   a data transmission interface for wirelessly transmitting data        from an external data processing device (C₂) to the control unit        (C₁),    -   the feedback sensor (F),    -   wireless energy transforming means, and    -   the injection port (32) for refilling the reservoir (R₁).

The invention claimed is:
 1. An at least partly implantable system forinjecting a drug into a patient's body, comprising an infusion deviceadapted for implantation inside the patient's body and at least onereservoir adapted for implantation inside the patient's body in fluidconnection with the infusion device to supply to the infusion device adrug to be injected into the patient's body, wherein the reservoircomprises at least one first compartment accommodating or adapted toaccommodate an infusion liquid and at least one second compartmentaccommodating or adapted to accommodate the drug in powder form formixing with the infusion liquid of the at least one first compartment,the system further comprising a mixing chamber for mixing the infusionliquid from the at least one first compartment with the drug from one ormore of the at least one second compartment, wherein the arrangement issuch that the drug is releasable from the at least one secondcompartment into the mixing chamber in powder form so that, wheninfusion liquid from the at least one first compartment is urged throughthe mixing chamber towards the infusion device, the infusion liquid willtake with it the drug released from the at least one second compartment,wherein the system further comprises at least one of: a plate having twolarger opposite sides being a first and second side, wherein the atleast one compartment is mounted so as to open towards a first side of aplate and wherein the opening mechanism is adapted to act on the atleast one second compartment so as to open to said first of the plate,and a tape wound up on a reel, wherein the at least one secondcompartment is mounted on the tape wound up on the reel.
 2. The systemof claim 1, wherein the drug in the at least one second compartment is adrug for stimulating penis erection.
 3. The system of claim 1, whereinthe drug contained in the at least one second compartment is infreeze-dried form.
 4. The system of claim 1, wherein the number of thesecond compartments is 50 or more, in particular 100 or more.
 5. Thesystem of claim 1, wherein a plurality of the second compartments isliquid-tightly sealed against the at least one first compartment,wherein the system further comprises a mechanism for individuallyopening a connection between the second compartments and the mixingchamber.
 6. The system of claim 1, wherein the second compartments aremounted in the plate as displaceable drug containers and the openingmechanism is adapted to displace the drug containers relative to theplate such that they deliver their drug contents.
 7. The system of claim5, wherein the second compartments are mounted in a plate which isrotatable so as to allow the drug containers to be brought intoalignment with a conduit upon rotation of the plate.
 8. The system ofclaim 1, wherein the tape is contained in a replaceable cassette.
 9. Thesystem of claim 1, wherein a plurality of second compartments isarranged on the tape in side-by-side relationship in a directiondifferent to the winding direction of the tape.
 10. The system of claim1, wherein at least a section of a periphery of the at least one firstcompartment is made from a flexible material permitting volume changesof the first compartment by deformation of the flexible material asinfusion liquid is filled into or drawn out of the at least one firstreservoir.
 11. The system of claim 10, wherein the flexible materialcomprises a polymer membrane.
 12. The system of claim 11, whereindrawing infusion liquid from the at least one first compartment causes anegative pressure in at least part of the reservoir.
 13. The system ofclaim 12, wherein the at least one first compartment comprises a gaschamber and an infusion liquid chamber, said chambers being separated bythe polymer membrane.
 14. The system of claim, 1, wherein the reservoirhas an injection port for refilling the reservoir with infusion liquid.15. The system of claim 14, wherein the injection port comprises amaterial which is self-sealing in respect of penetrations caused by areplenishing needle.
 16. The system of claim 1, wherein the infusiondevice comprises at least one infusion needle.
 17. The system of claim16, wherein the at least one infusion needle is disposed at least partlywithin at least one housing with a tip end of the at least one infusionneedle arranged for penetrating the at least one housing's outer wall inat least one penetration area, the system further comprising at leastone drive unit adapted for implantation inside the patient's body, theat least one drive unit being coupled to the at least one infusionneedle and arranged at least for advancing the tip end of the at leastone infusion needle so that the at least one infusion needle penetrates,upon advancement of the tip end or ends thereof, the housing's outerwall.
 18. The system of claim 17, wherein the drive unit is adapted foradvancing and retracting the infusion needle.